LAS VEGAS—An angry and defiant Denny Hamlin said Thursday that he will not pay a $25,000 fine but will instead appeal his penalty for criticizing NASCAR’s new Sprint Cup car after last week’s race at Phoenix International Raceway.

NASCAR announced the fine Thursday, saying it was penalizing Hamlin for comments that NASCAR officials said “denigrated the sport.” Hamlin had an angry reaction during a break in testing at Las Vegas Motor Speedway.

“I don’t believe in this,” Hamlin said. “I’m never going to believe in it. So as far as I’m concerned, I’m not going to pay the fine.

The Joe Gibbs Racing driver will have to pay the fine, or NASCAR may force him to. The NASCAR rule on payment of fines says:

“Failure to pay promptly may result in suspension. All unpaid fines of a Member may be collected by NASCAR by deducting the amount from the purse.”

While there is no definition of “promptly,” typically NASCAR does not allow drivers to race if they haven’t paid a fine prior to going out on the track. But typically fines are issued on Tuesdays and not Thursdays. Robin Pemberton, NASCAR vice president of competition, said Thursday that Hamlin has the option to appeal and that he is not currently in the window of having to pay the fine or face additional disciplinary measures.

Hamlin tweeted Thursday night that he would go through the process of appealing the fine, that “I am a person that worked very hard from the bottom to get to where I am today and somebody telling me that I (cannot) give my 100 percent honest opinion really bothers me.”

The short of the long of it is I believe I was severely disrespected by NASCAR by getting fined. I believe that... twitpl.us/t/ASR

The short of the long of it is I believe I was severely disrespected by NASCAR by getting fined. I believe that... twitpl.us/t/ASR

Hamlin said he believed he was fined for comparing NASCAR’s new Gen-6 racecar to its predecessor — the car of tomorrow, or COT. In the race at Phoenix, Hamlin started at the rear of the field and finished third, but he said his success came from pit strategy instead of passing other cars.

“I don't want to be the pessimist, but it did not race as good as our generation five cars,” Hamlin said in a postrace interview on pit road. “This is more like what the generation five was at the beginning. The teams hadn't figured out how to get the aero balance right.”

Hamlin said he was surprised by the fine and vowed not to talk about competition issues again.

“I’m not going to say anything for the rest of the year as long as it relates to competition,” he said. “You can ask me how my daughter is and talk to me after wins about what have you, but as long as it relates to competition, I’m out from here on out.”

Hamlin talked to the media for less than three minutes and answered questions succinctly before getting more agitated.

“The bad part of it is I feel like I’ve been a pretty good spokesman for them in being positive when things aren’t always positive,” Hamlin said.

“They just lost one small spokesman today. That’s all.”

As he continued to talk, the more flabbergasted Hamlin became. Considering that there was no pass for the lead after Lap 127 of the 316-lap race, the race was panned by many fans and others on social media.

Other drivers talked about the difficulty of passing but did not say it was worse than the previous car, which NASCAR felt never was embraced by fans in part because of negative driver comments.

“It’s an opinion — it’s not even a bad one,” Hamlin said. “I have to be careful. I don’t want to make things worse than they already are and this is something that was absolutely nothing (and) got blown into something.

“It’s just going to be worse for them, so let them deal with it.”

Hamlin indicated that other drivers have given strong opinions and not been fined. Defending Cup champion Brad Keselowski was talked to by NASCAR officials at Daytona about recent critical comments of NASCAR but was not fined.

“Ultimately I’m not OK with it,” Hamlin said. “This is the most upset and angry I’ve been in a really, really long time about anything—anything that relates to NASCAR.

“You have strong opinions about a lot of things, whether it be (Jeremy) Clements’ suspension (for a racial slur), things like that. A lot of people hold their tongue, some people don’t, like Brad.

“But the truth is what the truth is.”

Pemberton said drivers simply could not criticize the quality of racing, NASCAR’s core product.

“It’s more of a matter of fact that you can’t criticize your core product and what you’re trying to do,” Pemberton said. “Constructive criticism is one thing, but there's different statements that people made that are damaging.

“That's where we won't tolerate those types of things. … It’s fair to say any type of negative comment doesn’t do you any good.”

Pemberton said the appeals process is the same as any competition-related penalty with a three-member panel hearing it and a final appeal to the chief appellate officer.

“The fine is supposed to be paid as soon as possible but we’re not in any of those windows yet where it seems to be a problem (that he hasn’t paid),” Pemberton said.